小程序实现授权登陆的解决方案

{
"pages": [
  "pages/home/index", 
  "pages/login/index",
   ...
  ]
}

const App = getApp()
import { loginModel } from '../../models/login.js'
import { MineModel } from '../../models/mine.js'
import { encodeUnicode } from '../../utils/index.js'
const ModelLogin = new loginModel()
const Modelmine = new MineModel()
Page({
 data: {
  logged: !1,
  isauth: false,
  locked: false
 },
 onLoad: function(options) {
  // 返回到之前要刷新
  var pages = getCurrentPages() // 获取页面栈
  var prevPage = pages[pages.length - 2] // 前一个页面
  prevPage.setData({
   isBack: true
  })
 },
 onShow: function() {
  // 如果已经授权则显示登录,直接登录不调用授权
  App.WxService.getSetting().then(res => {
   if (res.authSetting['scope.userInfo']) {
    this.setData({
     isauth: true
    })
   }
  })
  //token 不能在page外面定义，变量写在 page 外面有缓存
  const token = App.WxService.getStorageSync('utoken')
  // 如果有token显示已经授权
  this.setData({
   logged: !!token
  })
  token && setTimeout(this.goBack, 1500)
 },
 login() {
  this.wechatSignUp()
 },
 goBack() {
  // 返回登录之前的页面
  wx.navigateBack({
   delta: 1
  })
 },
 // 登陆注册
 wechatSignUp(cd) {
  // 上锁如果正在请求接口那么就返回
  if (this.data.locked) {
   return
  }
  this.data.locked = true
  //注册或者登陆获取token
  let code = ''
  App.WxService
   .login()
   .then(data => {
    code = data.code
    wx.setStorageSync('logincode', data.code)
    return App.WxService.getUserInfo()
   })
   .then(data => {
    // 请求后台登录注册接口
    return ModelLogin.wechatSignUp({
     encrypteData: data.encryptedData,
     iv: data.iv,
     rawData: encodeUnicode(data.rawData), // 编码
     signature: data.signature,
     code: code
    })
   })
   .then(data => {
    this.data.locked = false
    if (data.data.token == '') {
     wx.showToast({
      title: '登录失败',
      icon: 'none'
     })
     return
    }
    App.WxService.setStorageSync('utoken', data.data.token)
    // 访问后台接口获取用户信息
    ModelLogin.getVipInfo({ token: data.data.token }).then(res => {
     App.globalData.userInfo = res.data.userInfo
     // 返回上一页
     this.goBack()
    })
   })
   .catch(err => {
    this.data.locked = false
    console.log(err)
   })
 }
})

<view class="login-container">
 <view class="login" wx:if="{{ !logged }}">
  <view class="app-info">
   <image class="app-logo" src="./s-logo@2x.png" />
   <text class="app-name">商城</text>
  </view>
  <view class="alert">
   <view class="alert-title" wx:if="{{!isauth}}">请同意授权</view>
   <view class="alert-title" wx:if="{{isauth}}">请登录</view>
   <view class="alert-desc">
    <view class="alert-text">为了让头号买手可以更好的为您服务</view>
   </view>
  </view>
  <button type='primary' wx:if="{{!isauth}}" class="sui-f16" open-type="getUserInfo" bind:getuserinfo="wechatSignUp">确认授权</button>
  <button type="primary" wx:if="{{isauth}}" class="weui-btn" bindtap="login">确认登录</button>
 </view>
 <view class="logged" wx:else>
  <image class="logged-icon" src="./s-logo@2x.png" />
  <view class="logged-text">近期你已经授权登陆过商城</view>
  <view class="logged-text">自动登录中</view>
 </view>
</view>